The present invention relates to a robot system, and more particularly to a robot system for use in a small-size industrial robot having a gripper arm which is unable to move perpendicularly toward a pallet on which workpieces are placed, or for use in a robot having no axis about which the gripper arm could angularly move for loading or unloading workpieces onto or from the pallet.
Industrial robots usually have a gripper arm extending from a robot body and include a gripper or hand on its distal end. The gripper serves to grip a workpiece placed on a pallet and to transfer the workpiece to another location via a predetermined path of movement. Such industrial robots are relatively large in size, and in ordinary installations a single industrial robot is located in the vicinity of a plurality of machine tools to service them. With recent rapid development of industrial robots, an increasing number of industrial robots is finding widespread use in small-scale factories and machine shops which have a relatively small work space. Since, however, such small-scale factories have only a limited number of machine tools of less diversified types, there is no strong demand in such machine shops for large-size industrial robots each capable of servicing several machine tools. Instead, the smaller factories prefer a small-size industrial robot which is effective enough to service a single machine tool. Large-size plants also find small-size industrial robots more advantageous for an increased rate of production for some applications in which a single machine tool is serviced by a single, less costly smaller industrial robot.
Conventional industrial robots however fail to meet the foregoing demands as they are dimensionally large, take up a large space, and are quite expensive.